Problem: What is the least common multiple of $3$ and $9$ ? $\text{lcm}(3, 9) = $
Answer: The least common multiple is the smallest number that is a multiple of $3$ and $9$. We know that $3 \times 9$ (or $27$ ) is a common multiple, but is it the least common multiple? Write out the multiples of $9$ until we find a number divisible by $3$. $9$ So, the least common multiple of $3$ and $9$ is $9$.